Bicycle connecting element, particularly for connecting carbon rear forks to frames

ABSTRACT

A connecting element, particularly for connecting rear forks, also known as monostays, made of carbon to bicycle frames. The connecting element is constituted by a first insert and a second insert which are mutually detachably associable at a first end by way of mechanical connection element. The first and second inserts are respectively associated, at a second end, advantageously by way of adhesives, with the stem of a carbon monostay, and are associable with, or rigidly coupled to, a tubular extension of the frame.

BACKGROUND OF THE INVENTION

The present invention relates to a connecting element, particularly forconnecting carbon monostays to bicycle frames.

Carbon front forks and rear monostays are currently increasingly used,in particular for competitive racing bicycles. This choice is due to theneed to have bicycle frames which combine high rigidity with greatlightness, and this need is effectively met by carbon-based materials.

When manufacturing frames, for example made of metallic alloys of steelor aluminum, it is necessary to deal with the problem of interconnectinga carbon element, the rear fork, and a metal element, i.e., the frame ora part thereof.

The prior art related to the use of carbon rear forks or monostaysprovides, as a solution to the described problem, for the use ofadhesives betweeen the two parts, which are shaped appropriately so asto be mutually interlocked.

The disadvantage of this system is the fact that the connection, onceprovided, is permanent and the monostay or rear fork can no longer beremoved from the frame.

In this manner, when necessary, for example for the replacement of oneof the two components due to breakage or technical choice, it is notpossible to separate the monostay and the frame.

SUMMARY OF THE INVENTION

The aim of the present invention is to solve the above problems,eliminating the drawbacks of the cited prior art, by providing anelement which allows to use a non-permanent connection system therebyallowing the carbon monostay to be detachably connected to the frame.Within this aim, an important object of the present invention is toprovide an element which allows to obtain a connection which adequatelywithstands the stresses applied during sports practice.

Another object is to provide an element which maintains the rigidity andlow-weight characteristics of the carbon rear fork or monostay.

Another object is to provide an element which is structurally simple andhas low manufacturing costs.

This aim and these and other objects which will become better apparenthereinafter are achieved by a connecting element, particularly forconnecting rear forks, also known as monostays, made of carbon tobicycle frames, characterized in that it comprises a first insert and asecond insert which are mutually detachably associable at a first end byway of a mechanical connection means, said first and second insertsbeing respectively associated, at a second end, advantageously by way ofadhesives, with the stem of said carbon monostay, and being associablewith, or rigidly coupled to, a tubular extension of said frame.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will becomebetter apparent from the following detailed description of a particularembodiment thereof, illustrated only by way of non-limitative example inthe accompanying drawings, wherein:

FIG. 1 is a perspective view of a detail of a bicycle frame with amonostay connected by means of the connecting element according to thepresent invention;

FIG. 2 is a first transverse sectional view of the first insert;

FIG. 3 is a front view of a first insert;

FIG. 4 is a second transverse sectional view of the first insert;

FIG. 5 is a side view of the first insert;

FIG. 6 is a side view of a second insert;

FIG. 7 is a first transverse sectional view of the second insert;

FIG. 8 is a second transverse sectional view of the second insert;

FIG. 9 is a lateral sectional view of the invention;

FIG. 10 is an exploded view of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures, the reference numeral 1 designates abicycle frame, advantageously made of metallic materials, particularlyalloys of steel or aluminum.

Said frame has, beneath and behind the saddle, toward the hub of a rearwheel, a tubular extension 2 which is internally hollow and isadvantageously circular, oval or teardrop-shaped.

A monostay, designated by the reference numeral 3 and made of carbon, isto be applied to said frame 1 and has, in an upward region, a stem 4 forconnection to a pair of lateral wings for connection to the hub of thewheel. For the removable connection between said stem 4 and said tubularextension 2, a connecting element, designated by the reference numeral 5is used, which is constituted by a first insert 6 and a second insert 7which are advantageously made of metal and have, in a transversecross-section, a perimetric shape which is similar to the perimetricshape of said tubular extension 2 or another appropriate shape accordingto requirements.

The first insert 6 and second insert 7 are detachably associable witheach other at a first end, designated by the reference numerals 8 a and8 b respectively.

The first end 8 b of said second insert 7 has a first axial seat,designated by the reference numeral 9, which is shaped complementarilyto said first end 8 a of said first insert 6, for the insertion thereofand its subsequent detachable coupling.

A first circular through hole 10 is provided radially with respect tothe lateral surface of said first end 8 a and is suitable for thepassage of appropriate means for mechanical connection between saidfirst insert 6 and said second insert 7.

The first end 8 b also is radially provided with a second hole,designated by the reference numeral 11, which is coaxial to said firsthole 10 but has a smaller diameter than said first hole and is not athrough hole.

In this manner it is possible to position, inside said first hole 10, abolt, designated by the reference numeral 12, which is composed of ascrew 13 and a nut 14, which interact with a registration pin 15 whichis positioned beforehand inside said first end 8 a, at a suitable secondseat which is designated by the reference numeral 16 and is formed atthe longitudinal central axis.

The registration pin 15 is advantageously designed to prevent therotation of said nut 14 with respect to said screw 13.

The head of said screw 13 is wider than the diameter of said second hole11, so that once said first end 8 a has been inserted in said first seat9 of said first end 8 b, the activation of the head of said bolt 12causes an axial movement, in opposite directions, of said screw 13 andsaid nut 14.

The free ends of said screw 13 and said nut 14 rest and abut againstfacing and complementarily shaped walls 17 which are internal to saidfirst end 8 b of said second insert 7; this entails the mutual lockingof the two components.

The first insert 6 and the second insert 7 have, in opposite positionswith respect to the respective first ends 8 a and 8 b, second ends whichare respectively designated by the reference numerals 18 a and 18 b.

The second end 18 a has a larger cross-section than said first end 8 a,which is connected thereto by means of a wing, designated by thereference numeral 19, which advantageously has the same shape anddimensions as the outer surface of the stem 4 of said monostay 3.

The stem 4 has, in its end part, a third axial seat, designated by thereference numeral 20, inside which it is possible to insert,advantageously by gluing, said second end 18 a, whose outside diameteris approximately equal to the inside diameter of said third seat.

If allowed by the materials, said tubular extension 2 is appropriatelyrigidly coupled to said second insert 7 by stable connection or bycasting during the manufacture of the frame.

Use of the connecting element according to the present invention istherefore as follows: with reference to FIG. 1, the reference numeral 1designates a frame which has a tubular extension 2 which isadvantageously rigidly coupled, for example during casting, to a secondinsert 7.

A first insert 6 is inserted, advantageously with the application ofadhesive, in the third seat 20 formed in a monostay 3 of a frame 1, sothat the wing 19 abuts against the edge of said monostay.

A registration pin 15 is then placed in the appropriate second seat 16formed inside the first end 8 a of said first insert 6.

The registration pin is designed to support a bolt 12 during theinsertion thereof in a first hole 10 formed in the first end 8 a of saidfirst insert 6.

After arranging the first insert 6 so that said first end 8 a enters afirst seat 9 formed in said second insert 7, one acts through a secondhole 11, formed in said second insert, so as to partially unscrew thescrew 13 from the nut 14 of said bolt 12.

This process causes said screw 13 and said nut 14 to press on therespective inside walls 17 of the second insert 7, with the consequentdetachable mutual coupling of the two inserts and therefore of the metalframe and the carbon monostay.

It has thus been observed that the invention has achieved the intendedaim and objects, a connecting element for detachable connection betweena metal bicycle frame and a carbon monostay having been provided.

The invention is of course susceptible of numerous modifications andvariations, all of which are within the scope of the same inventiveconcept.

The materials used, as well as the dimensions that constitute theindividual components of the invention, may of course be more pertinentaccording to specific requirements.

The disclosures in Italian Patent Application No. TV99A000131 from whichthis application claims priority are incorporated herein by reference.

What is claimed is:
 1. A bicycle frame with a detachable carbonmonostay, comprising: a tubular extension provided at said fame; a stemprovided at said monostay; a connecting element constituted by a firstinsert and by a second insert each having respective first and,opposite, second ends thereof; mechanical connection means actuatablefor detachably connecting and locking said first ends of said inserts toeach other, and a first axial, shaped seat, provided at one of the firstends of said first and second inserts, said shaped seat being shapedcomplementarily to the other one of the first ends of said first andsecond inserts, said first and second inserts being connected to eachother by axial insertion of said other one of the first ends of thefirst and second inserts in said shaped seat provided at said one ofsaid first ends of the first and second inserts and mutually locked byactuation of said connection means, the second end of said first insertbeing rigidly coupled with the stem of the carbon monostay, and thesecond end of the second insert being rigidly coupled to the tubularextension of the frame, said first insert being further provided with afirst, transversal, circular through hole arranged at a lateral surfaceof said first end thereof for passage of said mechanical connectionmeans and said first end of said second insert being provided with asecond, transversal, blind hole which is coaxial to said fist hole andhas a smaller diameter than said first hole.
 2. A bicycle fame with adetachable carbon monostay, comprising: a tubular extension provided atsaid frame; a stem provided at said monostay; a connecting elementconstituted by first and second tubular inserts each having respectivefirst and, opposite, second ends thereof; mechanical connection meansactuatable for detachably connecting and locking said first ends of saidinserts to each other; a shaped seat provided at the first end of, andformed by an inside wall of said second insert, said shaped seat beingshaped complementarily to the first end of said first insert, the secondend of said first insert being rigidly coupled with the stem of thecarbon monostay, and the second end of the second insert being rigidlycoupled to the tubular extension of the frame; and a first through holecrossing transversally the first end of said first insert and whereinsaid first and second inserts are connected to each other by axialinsertion of the fiat end of the first insert in said shaped seatprovided at the first end of the second insert,d mutually locked by wayof said connection means which are actuated to so as to engage in saidfirst through hole of said first insert and press on the inside wall ofsaid second insert.
 3. The frame with a detachable carbon monostay ofclaim 2, wherein said first insert and second insert have, in atransverse cross-section, a perimetric shape similar to the perimetricshape of said tubular extension.
 4. The frame with a detachable carbonmonostay of claim 2, wherein the second end of said fist insert iscoupled with the stem of the carbon monostay by way of a suitableadhesive.
 5. The frame with a detachable carbon monostay of claim 2,wherein said fist end of said second insert is provided with a second,transversal, blind hole which is coaxial to said fist hole and has asmaller diameter than said first hole.
 6. The frame with a detachablecarbon monostay of claim 5, further comprising: a second seat locatedinside said first end of said first insert and formed at a longitudinalcentral axis of the first insert, and a registration pin positioned insaid second seat.
 7. The frame with a detachable carbon monostay ofclaim 6, wherein said connecting means consist of a bolt, which iscomposed of a screw and a nut, and is insertable in said first hole soas to interact with said registration pin.
 8. The frame with adetachable carbon monostay of claim 7, wherein said screw has a headwhich is wider than a diameter of said second blind hole, so that uponinsertion of said first insert in said second insert, said head and saidnut rest on facing and complementarily shaped inside walls of said firstend of said second insert.
 9. The frame with a detachable carbonmonostay of claim 8, wherein upon actuation of said head through saidsecond blind hole said connection means are locked by an axial movementin opposite directions of said screw and said nut until the respectivefree ends thereof abut against facing side walls of said second insert.10. The frame with a detachable carbon monostay of claim 6, comprising athird axial seat in an end part of said stem of said monostay, saidsecond end of said first insert being coupled by gluing in said thirdseat and having an outside diameter which is substantially equal to aninside diameter of said third seat.
 11. The frame with a detachablecarbon monostay of claim 2, wherein said second end of said first insertis provided with a wing that has a larger cross-section than the firstend of the fist insert said wing having shape and dimensions identicalto those of an outer surface of said tubular extension.
 12. The framewith a detachable carbon monostay of claim 2, wherein said tubularextension is rigidly coupled to said second end of said second insert byany of a stable connection or casting during frame manufacture.